At the end of OotP Harry trys the Cruciatus Curse on Bellatrix.
She tells him that his "righteous anger" won't hurt her for long. That to use those curses you have to "enjoy" hurting others. Harry believes that Snape betrayed his parents. He thinks he saw Snape kill DD. This is still more along the lines of 'righteous anger.' Even when Harry found out that Wormtail HAD betrayed Lily and James, Harry didn't want Sirius to kill Wormtail. So, I don't see Harry killing anyone - unless as flat out self defense. But even then, not an AK, but GG's sword perhaps.

__________________"If you gaze long into an abyss, the abyss will gaze back into you."Friedrich Nietzsche

Harry and co. have allways shown their courage through their own creativity. I agree that this won't end in cold blooded murder. I do think that it must end with Voldemort gone for good however. And this right here is exactly why there is so much security around this book. I think there isn't one person who believes that Harry will fail his destiny to vanquish Voldemort. but Vanquish is a word that JKR very carefully used in the prophecy.

The word does not mention death. You may defeat or conquer someone without killing them. But how? That is what we all want to know! The only real clue we have, is that mysterious power that is studied in the DoM . . . Love.

I think Harry is prepared to kill Voldemort, as that is in his mind, the only way he knows to get rid of him, I think he believes that he wants to Kill Voldemort, but somehow it won't happen that way.

__________________Where your treasure is, there will your heart be also.His memory will live on . . .

There is no place I know to compare with pure imagination; living there you'll be free, if you truly wish to be. _Willy Wonka

I think Harry believe he has to kill Voldemort - not that he wants to ... That is the gripper on this point, he doesn't have the stomach for it when it comes down to it.Snape - yeah, I think he could drag up enough hatred considering all the years of mental abuse from Snape plus all the factors he was contributing towards for his parents and then finally seeing Snape kill Dumbledore - I think there is a lot more intention there than Voldemort ... Voldemort he is told he has to kill but in effect he hasn't had the same impression on Harry as Snape.